Things Not To Let Me Do
1: Commit suicide, if for some reason I want to.
2: Do physical harm to anyone, if you’re aware of it.
3: Eat meat, if you can.
4: Eat pears. I hate pears, I don’t want to wake up and taste that.
5: Leave the area, or you, behind.
6: Get involved in big sociopolitical events.
7: Hurt animals, especially owls.
8: Develop an addiction.
9: Anything impossible.
— Paul Cornell, Human Nature (1995) (bolding mine)

Companions in Disguise: Martha Jones as a maid at the Farringham School for Boys [Human Nature]

Doctors in Disguise: the Tenth Doctor as John Smith, teacher at the Farringham School for Boys [Human Nature/The Family of Blood]

INTERN: You are a doctor yourself?
FOURTH DOCTOR: Well, sort of, yes.
INTERN: How do you do? Tell me, where did you qualify, if I may ask?
FOURTH DOCTOR: A place called Gallifrey.
INTERN: Gallifrey? No, I’ve not heard of it. Perhaps it’s in Ireland.
FOURTH DOCTOR: Probably.

— The Hand of Fear

WOMAN: Patient’s name?
LEELA: Uh, just the Doctor.
WOMAN: Place of origin?
LEELA: Gallifrey.
WOMAN: Ireland?
LEELA: Oh, I expect so.

— The Invisible Enemy

JOAN REDFERN: Where did you learn to draw?
JOHN SMITH/TENTH DOCTOR: Gallifrey.
JOAN REDFERN: Is that in Ireland?
JOHN SMITH/TENTH DOCTOR: Yes, it must be, yes.

— Human Nature